Still picture processing for MPEG-2 video

Abstract

Still picture images are encoded and transmitted at reduced rates using the MPEG-2 standard. Video frames are captured for processing at a still picture capture rate that is lower than the video input frame rate. The captured frames are compressed as Intra frames at the input frame rate. Selected ones of the compressed frames are inserted in the MPEG-2 transport stream for communication to a decoder at a still picture repetition rate which is no less, in frames per second, than the capture rate.

Description

[0001]This application claims the benefit of U.S. Provisional Patent Application No. 60 / 171,773, filed Dec. 22, 1999.BACKGROUND OF THE INVENTION[0002]The present invention relates to digital video, and more particularly to a scheme for enabling still picture sequences (sometimes referred to as “still frame” sequences) to be communicated at a very low bit rate (e.g., under 200 Kbps) in the same transport stream that is carrying full motion video, multimedia and / or audio services such as conventional television programming. The techniques of the invention are particularly suitable, e.g., in providing still pictures for weather channels, album covers (e.g., text and graphics) that may accompany music channels, real estate sales channels, home shopping channels, and the like. For example, the invention will enable the album cover of a music video to be displayed while the video is playing, with the album cover video information being provided at a reduced bit rate (and consequent saving...

AI Technical Summary

Benefits of technology

The patent describes a method and device that allows for still pictures to be encoded and transmitted at a reduced rate using the MPEG-2 standard. This is achieved by using a standard video compressor that processes still video frames in the same way as full motion video. To maintain a standard throughput for the compressor, a compressed video buffer is used to receive output from the compressor and provide frames of compressed video data at the reduced still picture repetition rate. In one embodiment, both current frames and previous frames are provided as input to the compressor, with the previous frames being stored in a buffer for subsequent output as previous frames. The still picture capture rate is between one and five times the repetition period, allowing for a new still picture to be captured every three seconds.

Problems solved by technology

This technique is not advantageous since it does not provide real-time processing of the frames and, as a result, requires additional hardware (such as a server) to store the precompressed files and deliver them when required.

This causes the compressor frame buffer pointers to freeze, which in turn causes the same frame to be repeated.

This sequence of operation adds complexity due to the requirement to set and re-set the still frame mode flag and to switch the compressor between P-frame and I-frame processing.

Images